The second phase of blood volume restitution following hemorrhage requires the development of extracellular hyperosmolality. One variable component of this increased osmolality is hyperglycemia which has been thought to be under the control of catecholamines released from the adrenal gland. These experiments will evaluate the interraction between state of nutrition and severity of bleeding in the gensis of hyperglycemic hyperosmolality. Furthermore, the role of sympathetic nervous system mediated hepatic glucose release in the production of post-hemorrhagic hyperglycemia will be investigated. The relative significance of sympathetic and hormonal (catecholamines, glucagon) contributions to hyperglycemia will be evaluated following small (10%) and large (30%) hemorrhage in both fasted and fed animals which have previously undergone selective hepatic sympatectomy and/or adrenalectomy. By following in these animals the development of hyperglycemia and hyperosmolality and correlating this with measured blood volume changes in the period 2 to 24 hours following hemorrhage, the nature of the neural and hormonal contributions to phase two blood volume restitution will be defined. In particular, these studies should help document the extent to which both the early reflex and delayed hyperosmotic components of blood volume restitution following hemorrhage are mediated by the sympathetic nervous system.